In wireless communication, and particularly in broadband transmission, in addition to a first reception path, there are paths that arrive with a delay, by reflections from obstacles such as buildings and mountains, thereby resulting in intersymbol interference (ISI). An environment such as this having a plurality of paths of arrival is known as a multipath environment. For example, in multicarrier transmission, such as in OFDM (orthogonal frequency division multiplexing), OFDMA (orthogonal frequency division multiple access), and MC-CDM (multicarrier code division multiplexing), a guard interval (GI) is added to the multicarrier time-domain signal so as to prevent ISI, as long as the delay path is within the GI. However, if a delay path exists that exceeds the GI, in addition to ISI, intercarrier interference (ICI) occurs because the periodicity of the FFT (fast Fourier transform) is destroyed. ISI and ICI greatly worsen the receiving performance.
Non-Patent Document 1 describes a technique of for reducing ISI and ICI by
Non-Patent Document 1 describes a technique of for reducing ISI and ICI by using turbo equalization. Specifically, the Non-Patent Document 1 describes the generation of a transmitted signal replica from the bit-log likelihood ratio (LLR) of the results of error correction decoding, and the use thereof to divide the multiple path received signal into a plurality of blocks and process only the desired signal in the frequency band, so as to suppress ISI and ICI, thereby achieving good receiving quality.